WASHINGTON--A new watchdog group report claims the Bush administration has been muzzling government scientists who research climate change, raising eyebrows among a small group of politicians assembled for a hearing here on Wednesday.

The 131-page document by a whistleblower organization called the Government Accountability Project documents a number of instances since 2001 in which scientists at government agencies have encountered obstacles to communicating their publicly funded research to major media outlets.

Examples most commonly consisted of "inappropriate" editing; delay and suppression of scientific reports and press releases; designating public affairs officers to "monitor" press interviews with scientists; and quashing interview requests before consulting with the scientist or diverting them to scientists who had arguably more tentative positions on links between greenhouse gas emissions and human activity.

"Some scientists have given up trying to issue press releases or even pursue media contacts," Tarek Maassarani, the report's primary author, told politicians at a two-hour hearing here convened by a U.S. House of Representatives science oversight panel.

Anecdotes for the report, titled "Redacting the Science of Climate Change" (PDF), came from both named and anonymous scientists working for the National Oceanic and Atmospheric Administration, NASA, the U.S. Environmental Protection Agency and the U.S. Geological Survey.

The watchdog group notes that it did not uncover any instances of "direct interference" with climate change research itself. Government scientists surveyed for the report generally said they believed research in that area was "of excellent quality," as well as "independent and impartial."

Still, Rep. Brad Miller (D-N.C.), the House panel's chairman, said the findings supply additional evidence that the oil and gas industry is pressuring the Bush administration to "manipulate public debate about climate change."

"We need to rely on sound, dispassionate scientific research to inform our decisions," he said.

Referring to climate change science, House Science Committee Chairman Bart Gordon, (D-Tenn.) voiced dismay that some continue to "try to create doubt where there is little doubt." He pointed to a recent report by the United Nations Intergovernmental Panel on Climate Change, whose findings were endorsed by 113 nations, in which scientists said, in Gordon's words, that they were "100 percent certain" that global warming is real.

Jeff Kueter, president of the George C. Marshall Institute, a research group that has challenged the extent to which humans have contributed to global warming, cautioned the public not to adopt the IPCC's findings too hastily. Deeming the underlying science "incomplete," he told the politicians, "Reasonable people can reach different conclusions about human impact (on global warming)."

James McCarthy, a Harvard University professor who formerly worked with the U.N. climate change panel and now serves as president-elect of the American Association for the Advancement of Science, said a "broad consensus" on the science of climate change has emerged over the past 25 years and suggested views to the contrary, including "disinformation campaigns" by Exxon-Mobil and other oil interests, rest on nothing but "smoke, mirrors and hot air."

Not all of the politicians present--which numbered four or five throughout most of the hearing--were concerned about the report's findings.

Rep. Dana Rohrabacher (R-Calif.), the sole Republican in attendance, fumed about what he perceived as attempts by previous administrations and the scientific community to suppress so-called contrarian positions on global warming, thus stifling debate on the source of the phenomenon. He said it was too early to say there's a "consensus" on the issue, claiming hundreds of "very respectable scientists" disagree with the likes of McCarthy and the U.N. panel.

Rohrabacher, who made headlines for joking at a recent hearing that global warming could have been caused by "dinosaur farts," also challenged the idea that limiting scientists from publicizing their findings through agency press releases was a bad thing.

"That's not suppression at all," he said, later adding: "There may be other scientists that disagree totally with that science."

Rep. Brian Baird (D-Wash.) took more of a middle-of-the-road approach, urging his colleagues to look out for "abuse or misuse of science on all sides."